A ligament is a piece of fibrous tissue which connects one bone to another within the body. Ligaments are frequently damaged (e.g., detached, torn or ruptured) as the result of injury or accident. A damaged ligament can impede proper motion of a joint and cause significant pain. A damaged ligament can be replaced or repaired using various procedures, a choice of which can depend on a particular ligament to be restored and on the extent of the damage. When ligaments are damaged, surgical reconstruction can be necessary, as the ligaments may not regenerate on their own.
An example of a ligament that is frequently damaged as a result of injury, overexertion, aging and/or accident is the anterior cruciate ligament (ACL) that extends between a top of the tibia and a bottom of the femur. A damaged ACL can cause instability of the knee joint, arthritis, and substantial pain.
ACL repair typically includes the use of a ligament graft replacement procedure which usually involves drilling a bone tunnel through the tibia and up into the femur. Then a ligament graft, which may be an artificial ligament or harvested graft, such as a tendon, is passed through a tibial portion of the tunnel (sometimes referred to as “the tibial tunnel”) across the interior of the joint, and up into a femoral portion of a tunnel (sometimes referred to as “the femoral tunnel”). One end of the ligament graft can then be secured in the femoral tunnel and another end of the graft is secured in the tibial tunnel, at the sites where the natural ligament attaches.
Another ligament that is often damaged and may need to be replaced is a posterior cruciate ligament (PCL).
A common ligament reconstruction procedure involves using an autograft, which is a patient's own tendon that would replace the damaged natural ligament. The autograft is often a hamstring tendon, though other tendons can be used (e.g., a patellar tendon). The ligament graft can also be obtained from a donor (“allograft”).
Ligament augmentation and replacement procedures typically require preparation of a harvested ligament graft using various techniques to secure the graft for passing through the drilled tunnels and to strengthen the graft prior to fixation. The preparation may involve cleaning and measuring the graft, and then affixing sutures to free ends thereof. The thus prepared graft can be tensioned prior to being inserted into the femoral and tibial tunnels.
FIG. 1 illustrates an example of a graft 100 prepared using a conventional whip-stitching (simple or locking) technique. A needle (not shown) or other suture passing instrument can be used to pass a suture 102 through the graft 100 to create stitches some of which are labeled as 102A and 102B in FIG. 1. The whip-stitching can have certain drawbacks. For example, it may cause trauma to the graft and undesirable excessive elongation of the graft when a load is applied thereto. This can compromise the quality of the graft 100 and create a risk of complications during the ligament reconstruction procedure.
Other existing graft preparation techniques include, for example, baseball stitching, roman sandal suture techniques, krackow and Prusik knots.
The conventional approaches to graft preparation, such as the whip-stitching technique described above, can be labor- and time-consuming and may take up a large portion of time during a reconstruction surgery. Placing a suture on the graft can be cumbersome and, when a graft is prepared using such techniques, the entire reconstruction procedure may be put on hold, which can contribute to increased costs of the surgery. In addition, the surgeon or other medical personnel sewing the stitches bears a risk of a needle-stick injury which can lead to potential infections.
Accordingly, there is a need for improved techniques for preparing grafts.